Phytochemical profile and antioxidant properties of leaves extracts from Posidonia oceanica (L.) Delile and their allelopathic potential on terrestrial plant species

Dichloromethane, chloroform, ethyl acetate and ethanol extracts obtained from Posidonia oceanica (L.) leaves, were examined in order to determine their total phenolic, flavonoid, flavonol, anthocyanin and condensed tannins contents as well as their antioxidant and allelopathic activities. The qualitative phytochemical analysis of crude extracts confirmed the presence of coumarins in dichloromethane, chloroform and ethyl acetate extracts. The antioxidant activity estimated using the DPPH assay was significantly more pronounced for the ethyl acetate extract (IC50 = 1.19±0.018 mg/mL) than that of the other extracts. The allelopathic effect against the seeds of Carum carvi (L.) and Foeniculum vulgare (Mill.) indicated that, depending on concentration, the extracts from the leaves of P. oceanic (L.) inhibited or stimulated at different concentrations the germination, shoot and root elongation of seedlings growth. The results of this study suggest that P. oceanica (L.) extracts could be useful as a natural source of health-promoting effects and herbicides.                     KEY WORDS: Posidonia oceanic (L.), Phytochemical profile, Phenolic compounds, Antioxidant activity, Carum carvi (L.), Foeniculum vulgare (Mill)   Bull. Chem. Soc. Ethiop. 2020, 34(3), 437-447. DOI: https://dx.doi.org/10.4314/bcse.v34i3.

Antifungal Activity of Volatile Components Extracted from Leaves, Stems and Flowers of Four Plants Growing in Tunisia

Volatile components extracted from the leaves, stems and flowers of Lantana camara, Malvaviscus arboreus, Hibiscus rosa-sinensis cv. red flowers and white flowers were tested against the fungi Alternaria solani, Botrytis cinerea, Fusarium solani f. sp. cucurbitae, F. oxysporum f. sp. niveum, Pythium ultimum, Rhizoctonia solani and Verticillium dahliae. The strongest inhibitory effect of the extracts was found with volatile components extracted from the stems and the flowers. Complete inhibition was achieved against V. dahliae. The weakest effect was against P. ultimum. Volatile components extracted from the leaves were not effective

Botanical and Genetic Identification Followed by Investigation of Chemical Composition and Biological Activities on the Scabiosa atropurpurea L. Stem from Tunisian Flora

Scarce information about the phenolic composition of Scabiosa atropurpurea L. is available, and no carotenoid compounds have been reported thus far. In this study the phenolic and carotenoid composition of this plant was both investigated and associated bioactivities were evaluated. Aiming to obtain extracts and volatile fractions of known medicinal plants to valorize them in the pharmaceutical or food industries, two techniques of extraction and five solvents were used to determine the biologically active compounds. Gas chromatography coupled to flame ionization and mass spectrometry and liquid chromatography coupled to photodiode array and atmospheric pressure chemical ionization/electrospray ionization mass spectrometry highlighted the presence of 15 volatiles, 19 phenolic, and 24 natural pigments in Scabiosa atropurpurea L. stem samples; among them, the most abundant were 1,8-cineole, chlorogenic acid, cynaroside, and lutein. Bioactivity was assessed by a set of in vitro tests checking for antioxidant, antibacterial, antifungal, and allelopathic (against Brassica oleracea L. and Lens culinaris Medik) effects. Scabiosa atropurpurea L. stem extracts presented a considerable antioxidant, antibacterial, and allelopathic potential, with less antifungal effectiveness. These results indicate that the volatile fractions and extracts from S. atropurpurea L. stem could be considered as a good source of bioactive agents, with possible applications in food-related, agriculture, and pharmaceutical fields. Genetic investigations showed 97% of similarity with Scabiosa tschiliensis, also called Japanese Scabiosa

Etudes antioxydantes et chromatographiques de types CPG/FID et CPG/SM de fractions volatiles de feuilles de la plante Lawsonia inermis L. de Tunisie

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Etudes chromatographiques de types CPG/FID et CPG/SM de fractions volatiles de fleurs de la plante Lobularia maritima L.

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Contribution a la valorisation de feuilles de la plante Posidonia oceanica L. de Tunisie par des etudes chimiques, chromatographiques et antioxydantes

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Seasonal chemical compositions and antifungal activities of Tunisian Lupinus pilosus Murr. volatiles

The chemical composition and antifungal activities of the volatile fractions from leaves, roots and flowers of Lupinus pilosus Murr. harvested in winter and spring were studied. The yields of volatiles ranged from 0.01 to 0.04%. Those in spring were higher than in winter. The GC and GC-MS analysis permitted us to identify 83 compounds. The harvest season and the studied organ affected qualitatively and quantitatively the percentage of the different constituents. Spathulenol (1.0 to 8.7%), globulol (2.3 to 8.7%), α-bisabolol (7.0 to 8.8%) and nonanal (2.8 to 16.3%) were the major compounds of the studied volatile fractions. Non- terpene derivatives (14.3 to 72.5%) and oxygenated sesquiterpenes (6.4 to 33.4%) were the most represented chemical classes. The antifungal properties depended on the studied organ and the harvest season. The fraction obtained from roots harvested in winter showed moderate antifungal activity against C. glabrata and C. krusei (ΦIZ= 10 mm

Chemical composition and antimicrobial activities of Tunisian Salsola vermiculata L.

The chemical composition of Salsola vermiculate L. leaves, roots and stems volatile fractions was determined by gas chromatography. The major compounds of leaves volatile fraction were carvone (52.2%) and β-caryophyllene (5.8%). The major constituents of roots volatile fraction were carvone (49.9%) and cumin aldehyde (4.4%). The stems volatile fraction was dominated by carvone (53%), limonene (17.4%) and linalool (11.3%). The antimicrobial activity of S. vermiculate leaves, roots and stems extracts was evaluated toward Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Acinetobacter baumanii. The ethanolic roots extract was the most active against S. aureus with a MIC value of 0.28 mg/mL. However, E. coli and P. aeruginosa were the most resistant bacteria. The antifungal activity was tested against Candida krusei, Candida parapsilosis and Candida glabrata. These activities were weak with inhibition zone diameters ranging from 6 to 9.5 mm

Chemical composition and in vitro evaluation of antioxydant and antibacterial activities of the root oil of Ridolfia segetum (L.) Moris from Tunisia

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